The present invention relates to a magnetic bubble memory device, more particularly it relates to improvements in the ejection system of a magnetic bubble memory cassette.
An apparatus utilizing a magnetic bubble memory device for storage of information and performance of logical operation has various advantageous characteristics such as a non-volatile characteristic, a high memory density, a small power consumption, a small size and light weight. Moreover, since the magnetic bubble memory device is a stationary device which does not include any moving mechanical elements but has a very high reliability, great expectations are held for future utilization of this magnetic bubble memory device as a console unit memory or the like. When the magnetic bubble memory device is used as a console unit memory, for example, a memory medium of a portable data recorder, the characteristics of a small size and a light weight are especially important among the above-mentioned characteristics of the magnetic bubble memory device. With this background, there has recently been proposed a method in which a magnetic bubble memory device is contained in a cassette separate from a main apparatus comprising a driving circuit. The reading circuit and the cassette type magnetic bubble memory device is removably attached to the main apparatus. When this method is adopted, since information can be conveyed very simply and since relatively large quantities of information can be contained in a compact cassette by virtue of the characteristic properties of the magnetic bubble memory device, information to be put into a central processing unit can be stored directly at a place where data is acquired. Therefore, a further increase in the processing efficiency can be expected.
When the magnetic bubble memory device is to be stopped, the revolving magnetic field for actuating bubbles in a bubble chip must be stopped at a predetermined angle so as to stop the bubbles at a predetermined position in a transfer pattern of the bubbles. If the bubbles are not stopped at the predetermined position, it becomes difficult to derive the stored data in the bubble chip or the data are destroyed. In a cassette type magnetic bubble memory device, the magnetic bubble memory cassette can be easily pulled out from the main apparatus during the operation of the device. Therefore, there is the possibility of destroying the stored data in the bubble chip by pulling the cassette out of the apparatus by mistake.
The present invention was made in order to obviate the above mentioned drawback of the magnetic bubble memory device of the prior art.